Patent RU-2766042-C1 (RU)
Title: Method for surgical replacement of full-thickness osteochondral defects of articular surface of talus with chondropathy and aseptic necrosis
Inventor: KOROBUSHKIN GLEB VLADIMIROVICH
IPC: A61P19/00
Filed: 2021-06-23
Granted: 2022-02-07
Abstract: FIELD: medicine. 
     SUBSTANCE: invention refers to medicine, namely to traumatology, and can be used for surgical replacement of full-thickness osteochondral defects of articular surface of talus in patients with chondropathy and aseptic necrosis. In the preoperative period, the localization of the area of the articular surface involvement and the depth of the subchondral bone involvement are determined, patient’s venous blood is sampled for preparation of autologous platelet-rich plasma, on the basis of which fibrin gel with adhesive capacity is prepared intraoperatively. With the patient lying on his/her back with a roller in the region of the middle one-third of the shin after an anesthetic treatment and application of a hemostatic tourniquet a linear incision is made in a longitudinal direction in a projection of medial malleolus 5–6 cm long, and a medial malleolus is approached. Under the control of an electro-optical converter, two wires with diameter of 2 mm are brought in parallel from the insertion point at the apex of the medial malleolus through the middle of the medial malleolus in the frontal plane in the cranial direction. Then, channels are formed in the medial malleolus along the inserted wires using a cannulated drill and a chevron osteotomy of the medial malleolus is performed, followed by visualization of the articular surface of the talus, wherein the apex of the chevron osteotomy is placed 2.5–4.5 cm in the proximal direction from the apex of the medial malleolus; the chevron osteotomy is started with an oscillating saw and ended with breaking the subchondral bone using a chisel. After visualization of the defect, surgical sanitation and debris are performed, and the depth of its introduction into the ankle bone is marked on the basis of magnetic resonance imaging data. Bone sampling device is used to remove a sclerotic aseptically changed tissue within a healthy bone and an articular surface. Formed bone defect is assessed intraoperatively. Based on the obtained magnetic resonance imaging data, the osteochondral autograft volume is planned. Non-loaded pre-Achillary region of the calcaneal bone is approached along the medial surface of the calcaneal bone in an oblique direction with incision of 3–4 cm. Osteochondral autograft bone tissue equivalent to the formed defect is taken using a bone sampling device. Osteochondral autograft is adapted according to the shape and volume of the defect of the talus and is placed under the control of an electro-optical converter in the area of the bone defect of the talus by the press-fit method. Before insertion into the bone defect, fibrin gel with adhesive capacity prepared by mixing preliminarily prepared fibrin serum with 0.5 ml of 10% calcium gluconate solution is applied on the osteochondral bone autograft surface. Shape and size of the cartilage defect for pre-modeling of the collagen membrane to the cartilage defect are determined using a sterile foil template. Before the collagen membrane is placed on the bone autograft installed in the defect, fibrin gel with adhesive capacity is applied on the surface of the collagen membrane and on the surface of the bone autograft. After implantation and checking the stability of the collagen membrane, the reduction and osteosynthesis of the osteotomy of the medial malleolus with 2 cannulated screws is performed under the control of an electron-optical converter. Layer-by-layer wound closure, plaster immobilization of the operated lower extremity from the distal phalanges of the toes to the upper one-third of the shin is performed with the foot brought into the dorsal flexion of 90°. At that, for preparation of fibrin gel with adhesive capacity, 8–10 ml of patient’s venous blood is sampled into a test tube, which is centrifuged for 5–6 minutes at 3,100 rpm with separation of fibrin serum of autologous platelet-rich plasma from fibrin clot, fibrin gel with adhesive capacity is prepared using 0.5 ml of 10 % calcium gluconate solution, and affected tissues are transferred for histological examination. 
     EFFECT: method provides restoring the structure and architectonics of the talus, reposition of the osteotomy by the sequence of techniques and applying the collagen membrane on the autograft. 
     4 cl, 3 ex